High fidelity amplifying apparatus



Nov. 5, 1957 s. H. MICHAEL 2,812,382

HIGH FIDELITY AMPLIFYING APPARATUS 3 Sheets-Sheet l Filed Nov. 12, 1954 JUGE/(PROOF HIGH FIDELITY AMPLIFYING APPARATUS Filed Nov. 12, 1954 5 Sheets-Sheet 2 NOV- 5, 1957 s. H. MICHAEL 2,812,382

HIGH FIDELITY AMPLIFYING APPARATUS Filed Nov. l2. 1954 3 Sheets-Sheet 5 WWW United States Patent O HIGH FIDELITY AMPLIFYING APPARATUS Stanley H. Michael, East Orange, N. J.

Application November 12, 1954, Serial N0. 468,274

4 Claims. (Cl. 179-1) The present invention relates to electronic apparatus and more particularly to amplifying apparatus for use in homes, auditoriums, sound trucks, or the like, whenever amplification of sound is desired.

Amplifiers for such use are now well known to the art and are commonly connected to a microphone for live broadcasting, to a record player for amplification of canned music, to a radio for the amplification of either FM or AM reception, or to a pickup connected to a musical instrument. Heretofore,` such amplifying apparatus generally has not been of a high fidelity type and it has been rather bulky and definitely of considerable weight. Due to the previous size and weight, transporting such apparatus has constituted quite a problem as has also the question of maintenance and repair. Also, it has not heretofore been considered possible to mount the amplifier power pack and the speaker together as an integral unit because of the effect yof the power pack o-n the sound waves emanating from the speaker,

It is accordingly the object of the 'present invention to provide an amplifying apparatus of exceptionally high l fidelity which is exceedingly compact and light in weight.

Another object of the present invention is the provision of a high fidelity amplifying apparatus which can be very readily installed and just as quickly disassembled for repairing.

Another object of the present invention is the provision of a high delity amplifying apparatus operable in any position which is readily interchangeable with other units.

Another object of the present invention is theV provision of a high fidelity amplifying apparatus wherein such apparatus comprises a single unit including the necessary speaker together with its power pack all resiliently mounted to eliminate vibration and decrease distortion.

lA further object of the present invention is the provision of a perforated base for supporting the speaker and power pack as a single unit and wherein the power pack in no way interferes with the sound waves emanating from the speaker.

Still further objects of the present invention will become obvious to those skilled in the art by reference to the accompanying drawings wherein:

Figure l is a front elevational view of a high fidelity amplifying apparatus of the present invention mounted in its customary cabinet or carrying case,

Fig. 2 is a slightly enlarged view taken on the line ii-H of Fig. l looking in the direction of the arrows,

Fig. 3 is a sectional view taken on the line III-lll of Fig. 2 looking in the direction of the arrows,

Fig. 4 is a sectional view taken on the line IV-IV of Fig. 3 looking in the direction of the arrows,

Fig. 5 is a sectional view taken on the line V-V of Fig. 3 looking in the direction indicated by the arrows,

Fig. 6 is a rear view of a slight modification which the amplifier unit of the present invention may take, and

Fig. 7 is a sectional view taken on the line VilvVll 2,812,382 Patented Nov. 5, k1957 of Fig. 6r and looking in the direction indicated by the arrows.

Referring now to the drawings in detail, the amplifying apparatus of the present invention, as shown in the several figures, comprises a cabinet or carrying case 5 which may be of wood, metal, plastic, or the like, and if a carrying case, it is provided with a handle 6. Such cabinet or case 5 has a front panel 7 having hinges 8, at the bottom thereof, so that the panel may be pulled outwardly from the cabinet or case to expose the amplifying apparatus, with the outward movement of such panel about the hinges 8 being restricted by a suitable stop, such as a chain or the like 9. As will be noted from Fig. 1, such panel 7 has a grill 10 and a control panel 12 and immediately in back of this grill 10 a loud speaker` 13 (Fig. 2) is suitably mounted such as by means of Wood screws or the like 14.

By reference now more particularly to Fig. 2, it will be noted that in addition to the speaker 13, the amplifying apparatus of the present invention comprises a single compact unit which includes a perforated base member 15 to which the speaker 13 is secured by means of a shockand vibration-free mount, such as a bolt 16 surrounded by a soft rubber sleeve 17 and having soft rubber washers 18 positioned between the base 15 and the speaker magnet housing 19, as well as between the base 15 and a metal washer 20 under the head of bolt 16, as shown more in detail in Fig. 4. Alsoconnected to, and supported by, the perforated base 15 are the necessary sockets for the required amplifying electronic tubes 22, as well as the other power pack elements, such as a transformer 23, filter 24, resistors 25, rectifier 26, and the like. As can be readily seen from Fig. 2, the power pack is connectable to a source of electrical energy of the usual commercial potential by means of an extension cord and plug 27 and similarly certain elements of the pack are connected by wires 28 to the loud speaker, while other wires or a cable 29 connectsto the control unit carried by the panel 12.

The control panel 12 carries rotatable knobs 30 operable from the front for tuning the volume, as well as the treble, bass and depth tones, and the on-ofi switch 32,y

together with a pilot light 33 are also carried by this control panel with the latter being secured to the cabinet or carrying case panel 7 by suitable wood screws or the like 34. By reference to Figs. 2 and 3, it will be noted that the rear of the control panel 12 is provided with a slightly distorted U-shaped bracket 35 which is providedV for most every size and type unit, as the speaker decreases in size, the base likewise must decrease in diameter as otherwise the unit becomes unbalanced and unwieldy. In instances of this kind for speakers of five to about eight inches in diameter, a perforated base 15 of but slightly larger diameter would not provide sufiicient surface area to mount the various elements of the power pack, such as the transformer 23, filter 24, etc., and still be an integral one piece unit. Accordingly, a slight modification of the present invention has been shown in Figs. 6 and 7 wherein the perforated base 15 is provided with a substantially U-shaped bracket 38 having a short leg bolted or otherwise secured to the circular perforated base i5 as seen in Fig. 7. Like the base 1 5 this bracket 38is likewise perforated which not only decreases the weight of the base and bracket 38, but such, perforated members contribute to cooling the unit during operation and, more significantly, contribute to the high fidelity of the sound reception of the amp'lije Since the speaker naturally vibrates and also causes compression of air currents between the speaker cone and base, this tendency of the air to affect the sound waves otherwise occurring is eliminated, as there is no cushioning of the sound waves inasmuch as the air flows freely back and forth through the perforated base 15 and the bracket 38 when the latter is employed with smaller size units.

From the foregoing it should thus become obvious to those skilled in the art that a high fidelity` amplifying apparatus has been herein shown and des ribed which is compact and light in weight. Moreover, for maintenance and repair, the entire integral `unit comprising the speaker and power pack can be readily removed from the cabinet or carrying case and another very rapidly substituted therefor. By resiliently mounting the power pack and speaker to form an integral unit, and also by resiliently mounting the distortable elements of the control unit, a vibrationless and shock-proof amplifying apparatus is thus provided in which sound is reproduced with true fidelity `inasmuch as distortion is completely eliminated, since speaker volume or other elements of the unit cannot cause shock or vibration, and the latter is prevented from being transmitted to the amplifying apparatus from extrinsic sources.

Although several embodiments of the present invention have been shown and described, it is to be understood that still other modifications of the present invention may be made without departing from the spirit and scope of the appended claims.

I claim:

1. A high fidelity amplifying apparatus comprising a casing having a movable front panel, an integral amplifying unit detachably secured to said movable front panel including a perforated base member to eliminate compression of air currents which would otherwise effect the sound waves from said amplifying unit, amplifying power pack elements carried by said perforated base member, a loud speaker resiliently secured to and supported by said perforated base member on the opposite surface thereof to said amplifying power pack elements to prevent shock and vibration from distorting the reproduction of sound by said speaker, and a control panel mounted on the movable front panel of said casing having control knobs for adjusting the bass, treble and depth tones emanating from said speaker and said control panel CII 4 t having a resiliently mounted bracket for supporting fragile electronic tubes.

2. A high fidelity amplifying apparatus comprising a casing having a front panel hinged at the bottom thereof and movable outwardly to an angular position to facilitate access to apparatus housed therein, an integral amplifying unit detachably secured to said movable front panel including a perforated base member, amplifying power pack elements carried by said perforated base member, a loud speaker resiliently secured to and supported by said perforated base member to prevent shock and vibration from distorting the reproduction of sound by said speaker, and a control panel mounted on the movable front panel of said casing having control knobs for adjusting the bass, treble and depth tones emanating from said speaker and said control panel having a resiliently mounted bracket for supporting fragile electronic tubes.

3. A high fidelity amplifying apparatus comprising a perforated base member to eliminate compression of air currents which would otherwise effect the sound waves from said amplifying apparatus, amplifying power pack elements carried by said perforated base member, and a loud speaker resiliently secured directly to and supported by said base member on the opposite surface thereof to said amplifying power pack elements to prevent shock and vibration from distorting the reproduction of sound by said speaker.

4. A `high fidelity amplifying apparatus comprising a perforated base member to eliminate compression of air currents which would otherwise effect sound waves from said amplifying apparatus, a loud speaker resiliently secured to and -supported by said perforated base member to prevent shock and vibration from distorting the reproduction of sound by said speaker with the diameter of said speaker being substantially equal to the area of one surface of said perforated base member, amplifying power pack elements mounted on one surface of said perforated base member opposite to that of said loud speaker, and a perforated bracket carried by said perforated basemember for supporting still ladditional power pack elements where the area of said perforated base member is insufhcient to accommodate all the necessary power pack elements.

References Cited in the file of this patent UNITEDV STATES PATENTS 1,988,132 Murray Jan. 15, 1935 2,154,705 Schultz Apr. 18, 1939 2,567,829 Suthann Sept. 11, 1951 2,587,684 Bauer Mar. 4, 1952 

